Method of assembling headers and tubes



.Jul 8, 1947. E, A FI LD 2,423,697

METHOD OF ASSEMBLING HEADERS AND TUBES Filed Dec. 24, 1943 INVENTOREDWARD L.GARFIELDV Patented July 8, 1947 l /IETHOD 0F ASSEMBLING HEADERSAND TUBES Edward L. Garfield, Scarsdale, N. Y., assignor to Ice AirConditioning 00. Inc., New York, N. Y., a corporation of New YorkApplication December 24, 1943, Serial No. 515,521

3 Claims.

This invention relates to improvements in heat exchangers and animproved'method of manufacture and assembly thereof.

An object of this invention is to provide a heat exchange device havinga plurality of finned tubes forming steam passages secured in fluidtightrelation to concentric headers and mounted in a supporting frame.

Another object of this invention is to provide a novel method ofassembly of the tubes and headers.

Other and more detailed structural and procedural objects aresuccessfully secured by means of the invention herein disclosed as willbe apparent from the following description of one embodiment of theinvention and method of assembly thereof.

This invention resides substantially in the combination, construction,arrangement, relative location of parts, steps and series of steps, allas disclosed herein.

In the accompanying drawings,

Figure 1 is a vertical, cross-sectional view through a heat exchangerembodying the subject matter of this invention; 7

Figures 2, 3 and 4 are diagrammatic views illustrating the method ofassembly of the tubes and headers.

The heat exchanger herein disclosed while of a construction suitable foruse in cooling systems, is particularly adapted for use in heatingsystems. Heat exchangers for heating systems of the type hereindisclosed have heretofore frequently employed cast iron headers intowhich the steam tubes are expanded, with the inevitable result that asexpansion and contraction continue leaks develop at the expanded joints.In accordance with the construction herein set forth, cast iron headershave been eliminated and standard tubes of suitable material such ascopper, brass, steel and the like are employed, into which the steamtubes are secured, as for example by soldering, brazing or welding. Theresult is a permanently fluidtight construction which cannot readilydevelop leaks as the result of expansion, contraction, evaporation andother deteriorating forces.

Furthermore, in accordance with the construction herein disclosed, thesteam supply and return conduits are telescoped and are not physicallyconnected, except at the ends, so that deteriorating stresses due toexpansion and contraction cannot easily develop.

In addition there is provided a novel method of assembly of the headersand tubes, which makes 2 it possible to use ordinary cylindrical tubingfor them.

In the construction illustrated in the drawings the heat exchanger is ofthe type through which cold air is driven at relatively high velocitiesfor the purpose of heating it on its way to the space to be heated. Asillustrated, it comprises a framework which may be of rectangularconfiguration composed of transverse top and bottom members i and 2connected together by vertical members 3 and It in any suitable manner,as by welding or brazing. Within the framework thus formed is mounted aninner frame composed of somewhat similarly shaped channel members inwhich case, however, the top transverse channel member 5 is shallowerthan the bottom transverse channel member 6. The inner channel membersare secured to the outer channel members in any suitable manner as bywelding or brazing. As is clear from the drawings, all of these channelmembers may be made of sheet material of suitable characteristics suchas for example galvanized sheet steel of suitable gauge. This materialcan be readily worked to shape, punched with openings V as required, andotherwise manipulated in accordance with standard practice.

Extending transversely of the framework and within the housing 5 thusformed are the headers comprising a pair of plain cylindrical tubes 1and 9, each of which is closed or sealed at the end to form a fiuidtightcasing. As illustrated in Figure 1, the end of the tube 1 is closed by adisc 8 as would be the other end of the tube, not shown. Likewise, oneend of the tube 9 is closed by a disc Ml as is the other end. Extendingthrough the disc 8 in fiuidtight relation and into the disc l0. likewisein fiuidtight relation, is the steam supply connection H. The outerheader 1 contains the condensate return connection l2.

In the structure illustrated each of the headers is provided with tworows of tubes lying in parallel planes, which in turn intersect theplanes of the drawing. Thus the outer header 1 is provided with two rowsof tubes l3 and M which are respectively brazed or welded or otherwisesecured thereto at the joints l5 and I6 respectively. The outer or upperends of the'tubes I3 and I4 are closed off in any suitable manner, as bymeans of discs attached thereto to form fiuidtight joints. Telescoped tothe tubes l3 and it are the inner tubes l9 and 20 which extend intoopenings in the inner header 9 and are attached thereto by brazing,welding or the like, as indicated at ill and 22 respectively. The outeror upper ends ofthe tubes #9 and 23 are open to the tubes or coils.

Figure 3.

the seals 22. .2 an'dt3 of the drawings, 'theitubes .1 9.31 straight theinterior of the tubes I 3 and I4. As is clear from the drawings, thetubes l9 and 2!] are not connected to the tubes l3 and M and are free tomove relatively thereto under expansion, contraction, evaporation andthe like, so that no stresses are set up therein likely to break theseals 2| and 22.

Likewise the :tubes l3 and H; are relatively free for movement withrespect to the framework. Thus they project through apertures in thechannel 5 and are not attached thereto so that they can easily moveunder the stresses developed. The header assembly is supported withinthe box 5 in any suitable manner, not shown, and desirably the inner.header 9 is :supported in spaced relation with respect to the outerheader 1 by any suitable form of spacing devices likewise not shown.

This construction involves a problem of .assembly, the solution of whichinvolves an unobvious method of procedure. Heretofore structures of thisgeneral type were made up in ac 'cordance with rather intricatespecifications in -'erder to :provide a general relationship of parts asillustrated. Thus in one construction the header corresponding to theheader 1 has been .made of generally ov-al cross-section to which thenwelded longitudinally along its edges, to the .side of the oval tube sothat the inner tubes vopen thereinto. trativeof the complicated andexpensive method This construction is but illus heretofore employed'toprovide a structure generally like "that illustrated herein. Obviouslysuch a construction is expensive because of the :special par-tsrequired, and particularly because of thernumber of manual operationsinvolvinga plurality of joints, requiring brazing or welding to, get atight construction.

:In accordance with the novel methodherein disclosed it is :first to be.noted that ordinary plain tubingmajy be'employed both for the headersand -As illustratedJinFigur'e .2, the

outer header is provided with two rows of large .holes '1" properlypla'ced and the inner header is :provided with two rows of smaller holes:9. assembling theconstruction these two tubes are telescoped asillustrated in Figure 2, the inner row of holes '1' :in'the :outer:header 1. The tubes l9 are then welded or brazed into the tube *9 toform theseals 21, as illustrated. The inner tube :'9 is then shifted-sothat itsother row of holes 9 .are exposed through the larger holes 1' ofthe =other row in :the outer tube 1, as illustrated in The inner tubes29 are then welded or lbrazed to'the'tube 9 through the holes .1 'toform As is vclearly'lillustrated in Figures :atztheztimethey aremountedin thehea'der 8 and "welded therein.

The two rows .Df .outer larger "tubes [3 and M :are then successivelywelded or brazed to the 4 tubes 1 whose ends may then be closed off inany suitable manner. After all the tubes i9 and 20 are welded in placethe inner header 9 is fastened in a, central position with respect tothe outer header 7, as indicated in Figure 1, and in any suitablemanner, as for example by means of the end discs 8. The outer tubes 83are likewise straight at the time they are positioned on the header Iand welded thereto. After all the tubes are in place and the innerheader is properly positioned, they will radiate from the headers in anangular relationship, as is clear from Figure 3. The upper ends of thetubes are then forced towards each other to cause them to bend slightly,as is clear from Figures 1 and 4, so as to bring .them into parallelrelation. The welding of the tubes in place while they are straightfacilitates ready access 'to the points of welding without interferencewith the welding operation. Thus by a relatively simple and yet, it isbelieved, unobvious procedure, the assembly of Figure .1 can .readily bemade from plain ordinary tubing as distinguished from the use ofspecialized parts and expensive operations such as the one described.above. The assembly of the complete structure is otherwiseconventional, a1- thoughit may be noted, because it is not clear fromthe drawings that the fins l8 on the outer tubes l3 and it are actuallyalready attached to these tubes at the time they are secured to theheader i. In other words, finned tubes are available as an article ofcommerce, and are used in preference to the procedure of satisfactorilyattaching fins to these tubes after they are mounted in place.

The use of a device of this type is well known. It may be noted howeverthat live steam is introduced through the connection H so that it may"flow upwardly through the inner tubes i9 and 28 to discharge at theirope ends into the outer tubes i3 and M. The steam andjhe condensationformed as the heat is extracted therefrom, flows downwardly around theinner tubes and within the outer tubes back to the header from which itis withdrawn through the condensate return l2. As is well known, aconstruction of this type is employed so that sufiicientheat from thefresh incoming steam traveling up through the inner tubes keeps thelower parts of the outer device sufficiently warm to prevent freezing ofthe condensate therein as would otherwise occur when, for example, anycold fresh incoming air flows through the tubes to be heated.

In view of the fact that there is no satisfactory general term for usein the claims which will include soldering, brazing or welding, the

attachment of the tubes to the headers will be defined as by weldingwith the intention, however, that this term is to include as well aswelding attachment by soldering or brazing.

From the above description it will be apparent to those skilled in theart that the structure hereindisclosed is novel in certain features asset forth in the appended claims, as well as the .method of assembly.While some variations in the construction and method of procedure may bedevised, I contemplate that some of them will be within the skill of theordinary mechanic'and the resulting product and procedure will thereforebe included within the scope of the appended claims. 'I desire thereforeto be limited only as required by the claims, rather than by theillustrative disclosure herein set forth.

What is claimed is:

1. A method of assembling headers andtubes comprising the steps oftelescoping a pair of said seamless header tubes, said header tubes eachhaving at least two rows of holes in the wall thereof, positioning theinner header with respect to the outer header so that the holes of theinner header are exposed by the holes of the outer header, welding tubesextending through the holes of the outer header in the holes of theinner header by operating through the holes of the outer header,shifting the inner header so that holes of its other row are exposed torespective ones or the holes of the other row of the outer header,positioning the inner header with respect to the outer header so thatthe holes of the inner header are exposed by the holes of the outerheader, welding tubes extending through the holes of the outer header inthe holes of the inner header by operating through the holes of theouter header, telescoping the larger tubes with said smaller tubes, andwelding the larger tubes to the outer header at the holes therein.

2. A method of construction and assembly as described comprisingtelescoping a pair of header tubes each having at least two rows ofholes in the wall thereof, positioning the inner header so that one rowof its holes are aligned with one row of holes of the outer header,welding tubes in the holes of the inner header through the holes of theouter header, shifting the inner header so that its other row of holesare aligned with the other row of holes in the outer header and weldingtubes in the holes of the inner header through the holes of the outerheader.

3. The method of assembling headers and tubes comprising the steps oftelescoping a pair of seamless headers, said headers each having atleast two rows of holes in the walls thereof, positioning the innerheader with respect to the outer header so that the holes of the innerheader 6 are exposed by the holes of the outer header, welding tubesextending through the holes of the outer header into the exposed holesof the inner header, said welding being performed through the holes ofthe outer header, shifting the inner header so that the holes of itsother row are exposed through respective ones of the holes of the otherrow of the outer header, welding tubes in the holes of the inner headerby operating through the holes of the outer header, telescoping largertubes over the so welded smaller tubes of the inner header, welding thelarger tubes to the outer header at the holes therein, positioning theinner header concentrically with respect to the outer header with thetubes of the two rows extending angularly with respect to each otherand'bending the telescoped tubes into parallel relationship to form twoparallel rows of telescoped tubes extending from the concentric headers.

EDWARD L. GARFIELD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,684,083 Bloom Sept. 11, 19282,357,156 Wilso Aug. 29, 1944 1,898,713 Carrier et a1. Feb. 21, 19332,216,778 Houdry Oct. 8, 1940 2,117,830 Van Der Beyl May 17, 19382,211,813 Franco-Ferreira Aug. 20, 1940 2,339,284 Modine Jan. 18, 1944663,677 Kirker Dec. 11, 1900 1,837,442 Jackson Dec. 22, 1931 2,229,032Ashley Jan. 21, 1941 84,977 Wesson Dec. 15, 1868

